I dreamt a song this morning, just before I woke up.
When this happens, I never register what has happened at first, and then have to remember to record it on to my phone or some other recording device.
Usually, I'm listening to it on the radio or watching someone sing it; this time it was a boy band and I didn't like the song, but let's see what happens. Unfortunately, I woke up before it got to the chorus.
The weirdest song dream was that I was at a deserted Butlins in the dark and could hear a strange reverberant sound coming from a distant building. I followed the music, and walked into a huge, deserted, dark, plain room with a stage at one end, where a little woman was lit by a spotlight, singing and dancing, and this is what she was singing: